Background: Little is known about the epidemiology of acute decompensated heart failure (ADHF) in patients admitted to intensive and coronary care units (ICU/CCU). Observational data may improve disease management and guide the design of clinical trials. Aims: EFICA is an observational study of the clinical profile, management and survival of ADHF patients admitted to ICU/CCU. Methods: The study included 599 patients admitted to 60 ICU/CCUs across France. Relevant data was recorded during hospitalisation. Survival was assessed at 4 weeks and 1 year. Results: The main cause of ADHF was ischaemic heart disease (61%); 29% of patients had cardiogenic shock. Mortality was 27.4% at 4 weeks and 46.5% at 1 year, increasing to 43.2% and 62.5%, respectively, when including pre-admission deaths. Shock patients had the highest [57.8% vs. 15.2% without shock ( p < 0.001)] and patients with hypertension and pulmonary oedema had the lowest 4-week mortality: (7%). Pre-admission NYHA class III -IV heart failure, not initial clinical presentation, influenced 1-year mortality. Conclusion: ADHF is a heterogeneous syndrome. Based on initial clinical presentation, three entities with distinct features and outcome may be described: cardiogenic shock, pulmonary oedema with hypertension, and Fdecompensated_ chronic heart failure. This should be taken into account in future observational studies, guidelines and clinical trials.